1. Field of the Invention
The present invention relates to a burner to be used for cooking.
2. Description of the Prior Art
In the ordinary natural combustion burner, as is well known in the art, combustible gas is injected from an injection nozzle disposed at the inlet of a mixing tube to draw the air into the mixing chamber from an air suction port. The mixing tube is shaped as a "venturi tube" surrounding the injection nozzle with a converging cylinder so that the necessary amount of air is drawn in and the mixture of gases may be burned. The natural combustion burner produces a heating power or maximum temperature of about 800.degree. C.
Chinese style cooking, however, requires a heating power or temperature of about 1,200.degree. C. so that the water is sealed into the material being cooked, such as vegetables or meat. The forced combustion burner for a high heating power, according to the prior art, forces compressed air from a blower into the venturi tube so that the combustible gas and the compressed air may be mixed and burned coming out of the mixing tube.
The forced combustion burner of the prior art has a constant flame hole area (i.e., the total area of the plurality of flame holes of the gas head) and mixes the combustible gas and the air in the mixing tube. In case the heating power or temperature is to be adjusted, therefore, both the flow rate of gas to be injected from the injection nozzle and the flow rate of air to be fed into the mixing tube have to be regulated. The regulation of both of the flow rates is complicated and trouble-some. In addition, the heating power or temperature is difficult to adjust to a predetermined level for each time of regulating so that it cannot be finely controlled.
Moreover, the compressed air to be fed to the mixing tube is at a high pressure, and each flame hole has a small diameter so that the flames emanating from the flame holes produce high volume and/or frequency combustion sounds to cause a serious noise problem. A gourmet kitchen should be a calm working area, and the combustion sound of a burner is counter productive in this regard. Moreover, the forced combustion burner has to be equipped with regulators for the gas and air rates so that it has a complicated construction which raises a production cost.